Non-catalytic oxidation of cyclodode-canecarboxaldehyde to cyclodode-canecarboxylic acid

ABSTRACT

CYCLODODECANECARBOXYLIC ACID IS PRODUCED BY THE OXIDATION OF CYCLODODECANECARBOXALDEHYDE. UNSUALLY HIGH YIELD OF THE ACID IS OBTAINED IN HIGH PURITY BY CONDUCTING THE OXIDATION REACTION AT LOW TEMPERATURES IN THE PRESENCE OF A LOWER CARBOXYLIC ACID (E.G., ACETIC ACID) WITH OUT THE AID OF A CATALYST.

United States Patent O 3,792,085 NON-CATALYTIC OXIDATION OF CYCLODODE- CANECARBOXALDEHYDE TO CYCLODODE- CANECARBOXYLIC ACID Jack Newcombe, Freehold, N.J., assignor to Cities Service Company, New York, NY. No Drawing. Filed Apr. 30, 1971, Ser. No. 139,143 Int. Cl. C07c 51/26 US. Cl. 260--514 R 6 Claims ABSTRACT OF THE DISCLOSURE Cyclododecanecarboxylic acid is produced by the oxidation of cyclododecanecarboxaldehyde. Unusually high yield of the acid is obtained in high purity by conducting the oxidation reaction at low temperatures in the presence of a lower carboxylic acid (e.g., acetic acid) without the aid of a catalyst.

BACKGROUND OF THE INVENTION Prior art The oxidation of hydrocarbons with air, oxygen or an oxygen-containing gas is generally a well-known reaction whose parameters and ramifications have been the subject of numerous studies and investigations over the years. These reactions are generally exothermic in nature and unless properly controlled, there is a great tendency toward a run-a-way reaction and hot spots formation which seriously interfere with the efficiency of the reaction and result in decrease in the yield of the desirable products. One approach to the elimination of these problems has been to conduct the reaction in the presence of a solvent or a liquid vehicle which serves to absorb the heat liberated during the reaction. Numerous solvents have heretofore been employed, such as, aromatic solvents, e.g., benzene, toluene, xylenes, etc., and aliphatic solvents, e.g., hexane, heptane, etc., and aliphatic carboxylic acids, notably acetic acid.

Despite the abundance of prior art in the field of oxidation of hydrocarbons, there still are certain hydrocarbon products which, for one reason or another, have not heretofore been produced in high yield and purity from the oxidation of their precursors. For example, there is some prior art relating to the production of cyclododecanecarboxylic acid from the oxidation of cyclododecanecarboxaldehyde which, even in the presence of acetic acid and a catalyst, results in low yield of the acid, of the order of 65 to 70 rnol percent. Thus, US. Pat. 3,089,- 904, issued May 14, 1963 to Lippincott et a1. discloses that cyclododecanecarboxaldehyde may be oxidized to cyclododecanecarboxylic acid, using air or any other oxygen-containing gas as an oxidizing agent in the presence of (a) benzene or heptane,

(b) acetic acid and a cobalt catalyst, (c) performic acid in formic acid,

(d) sodium dichromate and acetic acid.

This patent discloses that the oxidation reaction may be carried out at a temperature of 20 to 100 C. and 15 to 100 p.s.i.g. (See column 2, lines 46 to 56.)

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cyclododecanecarboxylic acid may be produced by the oxidation of cyclododecanecarboxaldehy de in the presence of acetic acid, using mixed catalyst of manganese bromide and cobalt bromide. While this patent discloses a respectable yield of crude product, it provides no basis for making a precise determination of the acid content of this crude.

Still another prior art directed to the oxidation of cyclododecanecarboxaldehyde to the corresponding acid is a Communication by W. Ziegenhein and W. Lang in Angew Chem. Int. Ed. 2 149 (1963). Although this Communication reveals high yield of the acid, i.e., there is no disclosure relating to the details of the oxidation reaction.

Thus, despite all prior attempts to produce the cyclododecanecarboxylic acid from the corresponding aldehyde, there is no known satisfactory method for carrying out such an oxidation reaction to produce high purity acid, in high yields.

SUMMARY OF THE INVENTION This invention contemplates the production of cyclododecanecarboxylic acid by the oxidation of cyclododecanecarboxaldehyde.

In one aspect, the present invention is directed to the production of cyclododecanecarboxylic acid in high yields and purity by the oxidation of cyclododecanecarboxaldehyde in the presence of lower carboxylic acids, (e.g., acetic acid) without the use of a catalyst.

Another aspect of this invention is concerned with the production of cyclododecanecarboxylic acid by the oxidation of cyclododecanecarboxaldehyde at low temperature, i.e., of the order of about 10 C. to 20 C., thereby producing high yields of the acids, i.e., about 90 mol percent or even higher, and in high state of purity.

These and other aspects of this invention will be more fully described in the ensuing discussion.

DETAILED DISCLOSURE OF THE INVENTION It has been unexpectedly discovered that cyclododecanecarboxaldehyde may be oxidized to cyclododecanecarboxylic acid in high yields by conducting the oxidation reaction in the liquid phase, in the presence of an oxidation promoting agent such as the lower carboxylic acids and preferably at low temperatures, most advantageously of the order of about l0 C. to about 20 C. It has further been discovered that unlike the disclosure of Lippincott et al., the aforesaid oxidation reaction may be conducted without the aid of a catalyst while still obtaining unusually high yields of the acids in high state of purity. It has additionally been discovered that not all solvents and/or liquid media facilitate the oxidation reaction in a similar manner or result in the same degree of conversion of the aldehyde to the acid. Thus, for example, it has been found that acetic acid as well as the lower carboxylic acids, e.g., formic acid, propionic acid, butyric acid, or mixtures thereof, can be employed as the oxidation promoting liquid media with greater elficacy than solvents such as benzene, toluene, heptane and other solvents of the kind mentioned by Lippincott et al.

Briefly, the present invention com-prises oxidizing the cyclododecanecarboxaldehyde, in the liquid phase, in the presence of an oxidizing promoting vehicle such as the lower carboxylic acids, preferably acetic acid and propionic acid, at low temperatures and at atmospheric pressure. Air, oxygen or other known oxygen-containing gases may be used as the source of oxygen. It has been discovered that the oxidation of cyclododecanecarboxaldehyde in this manner results in the formation of high yields of acids, i.e., in excess of 90 rnol percent. The oxidation of cyclododecanecarboxaldehyde to cyclodode- Since the oxidation reaction of this invention is conducted in the liquid phase, it is, therefore, necessary that the conditions employed be such as to maintain the reaction mixture in the liquid phase throughout the reaction period.

Although reaction temperatures as high as about 80 C. or higher may be employed, it seldom is desirable to exceed about 50 C. and it has been discovered that exceptionally high yield of the desired acid can be obtained by conducting the oxidation reaction at extremely low temperatures. Thus, it has been found that a temperature within the range of about C. to about 20 C. results in yields of the desirable acid, i.e., cyclododecanecarboxylic acid, which is about 90 mol percent or even higher. Naturally, the selection of the most optimum temperature will depend upon the particular carboxylic acid which is employed as the oxidation promoting liquid media, with higher temperatures (within the aforesaid temperature range) being employed for the higher acids so as to prevent their freezing and solidification.

The carboxylic acids which are suitable as oxidation promoting liquid media are the lower carboxylic acids, i.e., formic acid, propionic acid, acetic acid and butyric or isobutyric acids, or mixtures thereof. In particular, however, acetic acid and propionic acid have been found to be specifically well-suited for the purpose of this invention. These acids may be used as aqueous solutions of varying concentrations of the acids. For example, acetic acid may be used as glacial (100%) acetic acid, or as aqueous solutions of the acid containing, say, 60% acetic acid, etc.

The oxidation reaction of this invention can be conveniently carried out at atmospheric pressure. Although pressures somewhat is excess of atmospheric pressure may be employed, such higher pressures are neither necessary nor particularly desirable since the use of such higher pressures require high pressure equipment.

The oxidation reaction of this invention is a stoichiometric reaction. However, the amount of oxygen which is employed may be slightly in excess of the stoichiometric amount in order to insure adequate and complete oxidation of the aldehyde.

The ratio of the carboxylic acid to the aldehyde which is employed naturally will vary somewhat depending, inter alia, on the particular carboxylic acid which is employed. In general, the weight ratio of the carboxylic acid to the cyclododecanecarboxaldehyde may vary from about 1:1 to about 100:1, preferably from about 1:1 to about 50:1. When using acetic acid, this ratio may vary from about 1:1 to about 10:1, preferably from 1:1 to about 3:1. The optimum ratio for other carboxylic acids may be readily selected on the basis of the guidelines and the disclosure provided herein.

The present invention will now be illustrated in connection with the following examples. However, it must be understood that these examples are merely for the purpose of illustration and are not intended to limit the scope or the manner of carrying out these oxidation reactions.

EXAMPLE I A solution of 0.4623 mol of cyclododecanecarboxaldehyde (98.17 grams of 92.46 percent purity) in three mols of glacial acetic acid (180 grams) was charged to a 500 mol flask equipped with a hollow shaft through which oxygen could be introduced. The solution was maintained at 50 C. and oxygen was introduced therein at the rate of 10.5 liters per hour. The oxygen was introduced by passing it through a wet test meter and the off gases from the reaction flask were also passed through a wet test meter in order to determine the amount of oxygen which was absorbed in the reaction. After 333 liters of oxygen had been introduced into the solution, it was noted that 5.96 liters of the oxygen was absorbed. This corresponds to percent of the theoretical amount of oxygen necessary for the reaction. Thereafter, the reaction mixture was poured into 1,000 ml. of water and the resulting solution was stirred in order to precipitate the cyclododecanecarboxylic acid. The resulting precipitate was filtered, washed with water and dried to a constant weight of 103.1 gram of a white product which was determined to have a melting point of 7587 C. This product had an acid equivalent weight (i.e., neutralization equivalent) of 277 corresponding to 76.5 mol percent purity and a yield of 80.3 mol percent. When this product was recrystallized from hexane, its melting point was determined to be 97-98 C. with an acid equivalent weight of 213.7. This corresponds to an acid purity of 99.4 mol percent.

EXAMPLE 2 The procedure employed in this example was essentially the same as the procedure of Example 1. 0.4135 mol of the cyclododecanecarboxaldehyde (87.8 grams of 92.46 percent purity) was dissolved in grams of glacial acetic acid and the resulting solution was held at 20 C. Oxygen was added while agitating the reaction mixture over a 60-minute period. 5.1 liters of oxygen was absorbed corresponding to 100% of theoretical oxygen requirement, and no additional oxygen was absorbed by continued oxygen addition. The reaction mixture was worked up as in the previous example and dried to a constant weight. Thus, 92.9 grams of cyclododecanecarboxylic acid having a purity of 85.8 percent was obtained which had a melting point of 81-87 C. When recrystallized from hexane as in the previous example, the acid yield was determined to be 90.9 percent.

Thus, it is apparent from the foregoing examples that the oxidation of the cyclododecanecarboxaldehyde results in higher yields of the corresponding acid when the oxidation reaction is carried out at lower temperatures. Furthermore, it is noted from the foregoing examples that higher yields than those disclosed in Lippincott et al. can be obtained by the oxidation of cyclododecanecarboxaldehyde in the presence of acetic acid at lower temperatures even without the aid of a catalyst.

While the foregoing examples illustrate the oxidation reaction in a batch type operation, the method of this invention may also be carried out continuously or semi-continuously without sacrifice in yield or purity of the desired acid. Furthermore, while these examples and the foregoing description have been directed to the oxidation of the mono-aldehyde, the di-aldehyde and the tri-aldehyde i.e., cyclodecane-di-carboxaldehyde and cyclododecane tri-carboxaldehyde can be oxidized to their corresponding acids in a similar manner. In the case of oxidation of these latter aldehydes, somewhat lower yield of the acid will be produced.

Throughout the foregoing examples and description, the purity of the acid is determined as follows:

Theoretical molecular weight The calculated molecular weight may be determined as follows:

Normality of causticxto neutralize the acid sample It is apparent from the foregoing description that the present invention is susceptible of various modifications and revisions, both in the oxidation step as well as the product recovery step. Such modifications and revisions, however, are nevertheless within the knowledge of those skilled in the art and do not alter or affect the spirit of this invention.

What is claimed is:

1. A process for producing cyclododecanecarboxylic acid which comprises reacting cyclododecanecarboxaldehyde with an oxygen-containing gas in the liquid phase at a temperature about C. to about 20 C. in the presence of about 1-100 parts by weight of a lower carboxylic acid per part by weight of cyclododecanecarboxaldehyde and in the absence of a catalyst.

2. A process as in claim 1 wherein said carboxylic acid is propionic acid.

3. A process as in claim 1 wherein said carboxylic acid is acetic acid.

4. A process as in claim 3 wherein the weight ratio of acetic acid to cyclododecanecarboxaldehyde is from about 1:1 to about 10:1.

5. A process as in claim 3 wherein the weight ratio of the acetic acid to cyclododecanecarboxaldehyde is from about 1:1 to about 3:1.

6. A process as in claim 2 wherein the weight ratio of carboxylic acid to cyclododecanecarboxaldehyde is from about 1:1 to about :1.

References Cited UNITED STATES PATENTS 3,089,904 5/ 1963 Lippincott 260514 3,253,025 5/1966 Brill et a1. 260530 FOREIGN PATENTS 1,286,803 1/ 1962 France 260514 261,589 3/1911 Germany 260530 250,406 1/ 1963 Australia 260530 LORRAINE A. WEINBERGER, Primary Examiner R. GERSTL, Assistant Examiner 2273 3 UNITED STATES PATENT *OFFICE CERTIFICATE OF CORRECTION Patent 702 mm Dated Fnhruary 1? 107a Inventofls) Jack 'Newcombe It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

q Column 3, Iine 51 the word "is" should read --in--. Column 5, Iine '4, the number "100" should read --I000--.

Signed and sealed this 13th day of August 1974.

. (SEAL) Attest:

MCCOY M. GIBSON, JR. C. MARSHALL DANN I Attesting Officer Commissioner of Patents 

